Histrelin Halts Precocious Puberty

Premature puberty - or "precocious puberty" - is caused
by hormonal imbalance. It can cause girls to go through puberty as
early as age seven or eight years, well before they are ready to
begin sexual maturation.

Now, Israeli researchers have developed a method to stop the
process of precocious puberty using an implant of the drug histrelin.

The study was
published in Pediatrics in December and
reported by Reuters Health on December 26, 2005.

Histrelin strongly inhibits gonadotropin-releasing hormone (also
called luteinizing hormone-releasing hormone, or LHRH). LHRH is
produced by the hypothalamus; it signals the anterior pituitary
gland to secrete luteinizing hormone and follicle-stimulating
hormone.

"The histrelin implant consistently suppresses clinical and
laboratory parameters of puberty for one year and is a promising
new technique for treating central precocious puberty without the
pain and inconvenience of monthly injections," write authors Dr
Irving M Spitz, from Shaare Zedek Medical Centre, Jerusalem, and
colleagues.

Precocious puberty is usually treated by administering
intramuscular or subcutaneous gonadotropin-releasing hormone
agonist every 3-4 weeks. Although the method is usually effective
in suppressing clinical and laboratory parameters of puberty, the
injections are painful and require monthly clinic visits that may
decrease treatment compliance.

The researchers set out to determine whether a subcutaneous
histrelin implant would suppress release of estradiol and
gonadotropin. Release of these two hormones brings on puberty and
menstruation.

The study was small, consisting of 11 girls of average age six
years (age range 2-9 years) who had central precocious puberty. The
trial duration was 12 months, after which time Hirsch et al
compared results of the histrelin suppression with the effects of
standard treatment.

The researchers followed six girls for 15 months after implant
insertion; in the remaining five girls, researchers removed the
implant after nine months and inserted a new implant at the same
incision site.

Results showed that none of the girls had menstrual bleeding
whiel receiving the implant treatment, and mean breast-development
regressed somewhat, growth velocity decreased and bone-age
advancement was slowed during treatment.

Acceleration of bone maturation and growth velocity both
normally signal the end of growth in height.

At nine months after commencement of treatment, puberty hormones
remained suppressed in all 11 girls, and at 15 months the hormones
remained suppressed in the six girls who returned to have the
implant removed.

The results showed that all of the participants reported
decreased pain, discomfort and interference with school activity
and work, compared with standard monthly injections.

"A multicenter clinical trial is currently underway in the
United States," Dr Spitz told Reuters Health. "We are continuing to
follow our Israeli patients, and we plan to study (normal hormone)
recovery following implant removal at the completion of the course
of treatment."